1. Field of the Invention
This invention relates to production of a gasiform hydrocarbon fuel. More particularly, it relates to preparing a gasiform hydrocarbon fuel from a hydrocarbon fuel oil having a gravity of about 10.degree.-50.degree. A.P.I., and maintaining same in such form into a gasiform burner. In one of its more specific aspects, it is concerned with the production of a gasiform hydrocarbon fuel suitable for burning in reforming furnaces used for the production of synthesis gas.
2. Description of the Prior Art
A national dilemma exists as a result of a diminishing supply of natural gas and an increasing demand for it. The impact of the gas crisis is being felt nationwide in rising prices, in governmental regulations with respect to the consumption of natural gas, and in prohibitions against the use of natural gas in future industrial construction. It is imperative that alternate sources of low-cost gaseous heating fuels be developed.
U.S. Pat. No. 3,561,895 to H. D. Michelson is directed to a method for control of fuel gas combustion. Inspirated air to inspirating type burners is maintained constant when one vapor fuel, e.g., natural gas, is changed for another, by heating or cooling the fuel in response to density variation, and supplementally by adding enriching or diluting gases. Preferred fuels for said method are light hydrocarbons; however, such fuels are not economic for use in industrial furnaces, as compared with natural gas or fuel oils.
It has long been known to pyrolyze and/or partially oxidize hydrocarbon fuel oils into a high heating value "oil gas" or into low heating value gas containing carbon monoxide and nitrogen. However, neither of these gases is interchangeable with natural gas. More recently, patents have issued on methods for preparing from hydrocarbon oils, or residuals, a fuel gas which has essentially the same heating value as natural gas.
U.S. Pat. No. 3,712,800 to A. H. Schutte discloses converting residual oils into a fuel gas having a heating value of about 950 to 1,000 B.T.U. per standard cubic foot. The residual oil containing one or more metallic modifiers as catalysts (which may be naturally occurring in the oil or added thereto) is pyrolyzed in the presence of small amount of steam at 1,000.degree. to 1,400.degree. F. and pressures of 5 to 30 psig., and from the products of the pyrolysis a fuel gas is separated. This fuel gas is a mixture of methane, hydrogen and ethane/ethylene.
U.S. Pat. No. 3,784,364 to W. L. Slater et al. discloses production of fuel gas having a heating value between 150 and 1,000 B.T.U. per standard cubic foot. The gas is prepared by subjecting a hydrocarbon oil to partial combustion at a temperature of about 1,300.degree. to 1,600.degree. F. using air as the oxidizing medium and injecting additional hydrocarbon oil into the hot partial combustion products.
U.S. Pat. No. 3,838,994 to C. L. Aldridge discloses conversion of heavy hydrocarbons to a methane rich gas product by contact with steam in the presence of a non-molten particulate alkali metal containing catalyst at pressures greater than 200 psig. and average temperatures between 1,000.degree. and 1,500.degree. F. An oxygen-containing gas may be introduced into the reaction mixture to provide a portion of the heat requirement.
U.S. Pat. No. 3,928,800 to E. T. Child et al. is directed to production of a methane-rich fuel gas from high-sulfur hydrocarbonaceous fuel. The high sulfur hydrocarbonaceous fuel is gasified by partial oxidation with substantially pure oxygen at about 1,700.degree. to 3,100.degree. F. and a pressure of 1 to 250 atmospheres to produce a process gas stream which is cooled, cleaned and subjected to catalytic methanation over a sulfur-resistant catalyst.
In prior processes for production of gaseous fuels involving pyrolysis and/or partial oxidation of hydrocarbon oil at temperatures of 1,000.degree. F. or higher, from about 0.1 to about 10 weight percent, based on the hydrocarbon feed, of entrained particulate carbon is produced due to cracking of the hydrocarbon oil. Solid carbonaceous deposits form downstream from the reaction zone on the surfaces of vessels, lines, and heat exchangers. This entrained particulate carbon may be separated and recovered from the gas stream by known scrubbing and extraction processes but disadvantages of carbon recovery processes include the high cost of equipment and materials, and the operation of said recovery processes. Therefore, it would be desirable to provide a process which eliminates cracking of the hydrocarbon fuel oil to form entrained particulate carbon. Clearly, such process should avoid the prior art pyrolysis and/or partial oxidation of the hydrocarbon fuel oil.